1. Filed of Industrial Application
The present invention relates to an image generation system and program.
2. Description of the Related Art
There is known an image generation system which can generate an image as viewed within a virtual three-dimensional or object space from a given viewpoint. Such a system is very popular since one can experience a so-called virtual reality through it. Now considering an image generation system for playing a gun game, a player (or operator) can enjoy a three-dimensional shooting game by manipulating a gun-shaped controller (or shooting device) to shot targets such as enemy characters (or model objects) and the like which are displayed on a screen.
In such an image generation system, it is important that images can be generated with reality to improve the degree of virtual reality for players. It is thus desired that the motion of enemy characters is also represented with reality. In the conventional image generation systems, motion data for specifying a skeleton shape (or skeleton configuration) for each enemy character in each frame is previously prepared. Based on such motion data, a motion play (or motion animation) process is performed to represent the motion of that enemy character.
However, such a motion play process only based on the motion data has the following problems:
(1) Even though the position or direction of a player (or a player""s character controlled by the player or a virtual camera) varies or a shot (or bullet or the like) from the player hits the enemy character, that enemy character moves with the same motion at all times. Thus, the representation of motion becomes monotonous.
(2) If it is attempted to give variety to the motion of the enemy character to prevent monotonous representation, the motion data must be increased. However, since the capacity of a memory for storing the motion data is limited, variety of the motion is also limited.
On the other hand, the motion play process based on the motion data is advantageous in that it can move and arrange enemy characters in the same manner at all times.
Such a type of gun game proceeds according to a particular story, and a virtual camera always moves along a given pattern according to the story. If an enemy character moves irregularly, the virtual camera will not be able to take the enemy character. Thus, the game story cannot smoothly be developed.
However, the motion play process based on the motion data can move and arrange the enemy characters in the same manner at all times so that the enemy characters can surely be taken by the virtual camera at all times. It is thus desirable that such a motion play process is more effectively utilized.
The present invention is devised in the light of the above problems and has as an objective thereof the provision of an image generation system and program which can implement motion representation with more reality and variety using a less amount of data by utilizing a motion play process based on the motion data.
In order to solve the above problems, this invention provides an image generation system comprising: means for performing motion correction in which a skeleton shape of a model object specified by motion data is slightly changed based on hit information when the model object including a plurality of parts is hit; and means for generating images including an image of the model object. This invention also provides a computer-usable information storage medium which comprises information (a program, data or the like) for implementing (or executing) the above-described means. The present invention further provides a computer-usable program embodied on an information storage medium or in a carrier wave, the program comprising a processing routine for implementing (or executing) the above-described means.
The model object is formed by a plurality of parts, and the position or rotation angle of each part is specified by the position or rotation angle of the corresponding one of the bones defining the skeleton. However, the skeleton and bones will virtually be represented, but actually be in the form of data representing the position or rotation angle of each part.
Moreover, the skeleton shape specified by the motion data is slightly changed when the model object is hit by shot, punch, kick, impact or the like. This makes it possible to represent the reaction of the hit model object. As a result, only a single set of motion data is sufficient to implement the motion representation with more reality and variety.
Note that the skeleton shape specified by the motion data may be determined only by the motion data or may be the one already subjected to the other motion correction once at least.
The image generation system, information storage medium and program according to the present invention may perform the motion correction based on the hit information and a restoring force for returning the skeleton shape of the model object to an original skeleton shape specified by the motion data. The model object will be slightly vibrated by hit impact and the motion representation of with more reality and variety can be implemented.
The image generation system, information storage medium and program according to the present invention may perform the motion correction such that the amount of slight change of the skeleton shape by the hit information is gradually reduced as time passes. This makes it possible to represent the amplitude of vibration of the model object which is gradually reduced as time passes after the hit.
The image generation system, information storage medium and program according to the present invention may perform the motion correction while substantially fixing a position or rotation angle of a given part of the model object. This makes it possible to perform the motion correction in which the skeleton shape is slightly changed by the hit, while turning a first part (such as a head, hand or fire arm) of an object toward a given target position, or, while fixing a position or rotation angle of a second part (such as a foot) to a position of rotation angle specified by the motion data, for example. As a result, only a single set of motion data is sufficient to implement the motion representation with more reality and variety.
The image generation system, information storage medium and program according to the present invention may perform the motion correction while substantially fixing a position or rotation angle of the body coordinate system of the model object relative to the world coordinate system to a position or rotation angle specified by the motion data. This makes it possible to change the position or rotation angle of the body coordinate system of the model object in accordance with the motion data. Therefore, the skeleton shape of the model object (movement of each part) is changed by the motion correction, but the entire movement of the model object can be controlled to faithfully follow the motion data. As a result, even if the situation of game varies, for example, the virtual camera can positively take the model object at all times.
The image generation system, information storage medium and program according to the present invention may perform the motion correction after a first motion correction has been finished in which a given part of the model object is turned toward a given target position. Such motion correction through a number of steps makes it possible to implement the motion representation with more variety.
The present invention further provides an image generation system for generating an image, comprising: means for performing a first motion correction in which a skeleton shape of a model, object specified by motion data is changed, the model object including a plurality of parts, then performing a second motion correction in which the skeleton shape of the model object which has been changed by the first motion correction is further changed, . . . and finally performing an N-th (Nxe2x89xa72) motion correction in which the skeleton shape of the model object which has been changed by an (Nxe2x88x921)-th motion correction is still further changed; and means for generating images including an image of the model object. This invention also provides a computer-usable information storage medium which comprises information (a program, data or the like) for implementing (or executing) the above-described means. The present invention further provides a computer-usable program embodied on an information storage medium or in a carrier wave, the program comprising a processing routine for implementing (or executing) the above-described means.
This makes it possible to perform a multi-step motion correction process including the first through N-th motion corrections. Even if only a single set of motion data is used for a motion, that motion can be viewed differently if the first to N-th motion corrections are different, leading to the motion representation with variety.
In the image generation system, information storage medium and program according to the present invention, information for respectively enabling or disabling the first to N-th motion corrections may be set to the model object. This makes it possible, for example, to enable the first and second motion correction for a first model object, enable the first motion correction but disable the second motion correction for a second model object, and disable the first and second motion correction for a third model object. Therefore, even if the same motion data or program is used for a plurality of model objects, these model objects can perform different motions by changing the setting of the information. As a result, model objects which perform various motions can be easily provided.
The image generation system, information storage medium and program according to the present invention may perform the first to N-th motion corrections while substantially fixing a position or rotation angle of the body coordinate system of the model object relative to the world coordinate system to a position or rotation angle specified by the motion data. The skeleton shape of the model object (movement of each part) is changed by the first through N-th motion corrections, but the entire movement of the model object can be controlled to faithfully follow the motion data.
The present invention further provides an image generation system for generating an image, comprising: means for changing a skeleton shape of a model object which includes a plurality of parts such that a given part of the model object is turned toward a given target position and the skeleton shape of the model object is slightly changed when the model object is hit; and means for generating images including an image of the model object. This invention also provides a computer-usable information storage medium which comprises information (a program, data or the like) for implementing (or executing) the above-described means. The present invention further provides a computer-usable program embodied on an information storage medium or in a carrier wave, the program comprising a processing routine for implementing (or executing) the above-described means.
According to the present invention, the model object can be moved to faithfully follow the motion data, while turning a given part (such as a head, hand or fire arm) of the model object toward a given target position (a player""s character or a virtual camera, for example). If the model object is hit, its skeleton shape is slightly changed based on the hit information. As a result, a model object which performs an optimum movement as a target (or enemy character) of a shooting game such as a gun game can be implemented.